(1. 中國科學(xué)院 金屬研究所, 沈陽 110016;
2. 中國科學(xué)院 金屬腐蝕與防護(hù)國家重點(diǎn)實(shí)驗(yàn)室， 沈陽 110016)
摘 要: 采用機(jī)械合金化，隨后在620 ℃，58 MPa下熱壓制備了致密的塊體亞穩(wěn)態(tài)納米晶Ag50Ni50合金，用X射線衍射儀、掃描電鏡和透射電鏡研究了其組織結(jié)構(gòu)。晶格常數(shù)的精確測(cè)定結(jié)果表明，球磨200h后Ag在Ni中固溶度為4.96%±0.21%(摩爾分?jǐn)?shù))，Ni在Ag中固溶度為0.84%±0.30%(摩爾分?jǐn)?shù))，熱壓以后仍具有過飽和固溶度，Ag在Ni中為0.45%±0.11%(摩爾分?jǐn)?shù))，在相近溫度下穩(wěn)定化處理后進(jìn)一步脫溶。600～700℃時(shí)Ag在Ni中固溶度為(0.21～0.24)%±0.11%(摩爾分?jǐn)?shù))，Ni在Ag中固溶度小于0.1%(摩爾分?jǐn)?shù))。機(jī)械合金化粉末的晶粒度約為6nm， 熱壓后長(zhǎng)大至40～60nm，退火后又長(zhǎng)大至100～110nm。探討了晶粒度與內(nèi)應(yīng)力同時(shí)作用下X射線衍射峰的展寬問題和納米晶結(jié)構(gòu)對(duì)快速致密化的作用。
關(guān)鍵字: 塊體納米晶合金； 過飽和； 快速致密化； Ag50Ni50
Ag50Ni50 alloy prepared by hot pressing
of mechanically alloyed powders
ZHAO Ze-liang1，2， NIU Yan1，2, WU Wei-tao1，2
（1.Institute of Metal Research， Chinese Academy of Science，
Shenyang 110016,P.R.China;
2. State Key Laboratory for Corrosion and Protection,
Chinese Academy of Science, Shenyang 110016, P.R.China）
Abstract:A bulk nanocrystalline Ag50Ni50 alloy has been prepared by hot pressing of mechanically alloyed powder at 620℃ under a pressure of 58MPa. The microstructural characteristics of the alloy were studied by X-ray diffraction (XRD)， scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results show that after mechanical alloying for 200h， a solid solubility of Ag in Ni reached 4.96%±0.21%(mole fraction) and Ni in Ag reached 0.84%±0.30%(mole fraction). After hot pressing， the Ag-and Nirich phases in the alloy were still in a state with certain degreeof supersaturation， such as a solid solubility of Ag in Ni being 0.45%±0.11%(molefraction). The results also reveal that the solubility of Ag in Ni is (0.21～0.24)%±0.11%(mole fraction) and that of Ni in Ag is less than 0.1%(mole fraction) at 600～700℃. The grain size of the mehanically alloyed powders was about 6nm. After hot pressing, it grew to 40～60 nm and then after annealing treatment it grew further to 100～110nm. Furthermore， the influence of the variation of the grain size and the internal stress on the broadening of the X-ray diffraction peaks was evaluated in detail and the role of the nanocrystalline structure in the fast densification process of the powders was also discussed.
Key words: nano-crystallined bulk alloy； super-saturation； fast densification； Ag50Ni50
